Sunderland winger Adam Johnson was arrested on suspicion of having sex with a 15-year-old girl after she reportedly boasted about the affair and her father found out. Johnson, 27, was arrested at his home in County Durham on Monday after police received a complaint from the girl's father but has since been released on bail. It is understood the girl, who cannot be named for legal reasons, bragged about the alleged encounter to friends and on social media, the Daily Telegraph reports. Adam Johnson (pictured left and right with girlfriend Stacey Flounders) was arrested on suspicion of having underage sex with a girl, 15, after she reportedly boasted about the alleged encounter on social media . Johnson, who was signed for £10million in 2012, was then arrested and questioned for several hours. He has since been released on bail and suspended by Sunderland, pending the outcome of the police investigation. The Premier League footballer's arrest has come just weeks after his long-term girlfriend Stacey Flounders, 25, gave birth to the couple's first child Ayla Sofia. It was unclear if Miss Flounders and her daughter, who was born on January 8, were at home at the time of the player's arrest. But Miss Flounders's mother has defended the former Middlesbrough and Manchester City player, insisting he is '100 per cent innocent'. Talking about the couple's relationship, she told the Daily Mirror: 'They are still very close and are absolutely still together. He is 100 per cent innocent and we will stand by him. 'He hasn't been found guilty of anything. He is a great lad and has not done anything wrong. This is a horrible situation.' The 27-year-old millionaire was arrested at his six-bedroom mansion in County Durham (above) after the alleged victim's father reportedly complained to police, it has emerged . The £50,000-a-week player had been due to travel with the rest of the Sunderland squad to East Yorkshire for Tuesday's league game against Hull City before being suspended. A statement from Sunderland said: 'Sunderland AFC has confirmed that Adam Johnson has been suspended from the club, pending the outcome of a police investigation. No further comment will be made at the present time.' The FA refused to comment on Johnson's arrest. Johnson, who has represented his country 12 times, gained a reputation as a keen party-goer when he played for Manchester City five years ago. Johnson, who was signed for £10million in 2012, was arrested on Monday morning and questioned for several hours. He has since been suspended by Sunderland . The FA refused to comment on the arrest of the winger. Pictured: Johnson scored a late winner against Newcastle United at St James' Park last December . At the time, he was renting Cristiano Ronaldo's former house near Alderley Edge and would often be seen in the village socialising with fellow players and women. But three years ago, after returning to his native North East, Johnson began dating Miss Flounders. Friends say Johnson opted to live near a quiet hamlet to get away from the 'bright lights' of city life. On Monday, three unmarked police cars, a police van, several plain-clothed officers and a forensics team were seen at his house as he was questioned at a Durham police station. Johnson has been released on bail and will return to Peterlee police station (pictured) at a later date . It is unclear where the alleged assault is said to have taken place and police would not release any further details. Johnson was born in Sunderland and raised in Easington, County Durham, before joining Middlesbrough's youth academy as a 12-year-old. After making his Premier League debut for Middlesbrough in 2005 he was sold in February 2010 to Manchester City. He was signed by Sunderland three years ago. He failed to make the squad for the World Cup in Brazil last year, . In a statement, a Durham Police spokesman said: 'A 27-year-old man was arrested earlier today on suspicion of sexual activity with a girl under 16. He has been released on police bail pending on-going investigations. 'A blank firing pistol, which replicates the sound of real gunshots but does not require a licence to own, was also recovered during a search of the property.' Sorry we are not currently accepting comments on this article.
Adam Johnson was arrested on suspicion of having sex with a 15-year-old .
Schoolgirl, 15, reportedly boasted about alleged encounter on social media .
Johnson, 27, held at Durham mansion after her father complained to police .
Sunderland suspended player 'pending outcome of investigation'
Long-term girlfriend Stacey Flounders is reported to be standing by him .
The 25-year-old gave birth to couple's first child Ayla Sofia on January 8 .
Adam Johnson timeline: Sportsmail takes a look at his career .
Gus Poyet: Johnson's arrest was my toughest day in management .